Mechanical leveling chuck



Feb. 24, 1970 G. E. scum MECHANICAL LEvELim cnucx 2 Sheets-Sheet 1 FiledNov. 16, 1966 INVENTOR. GEORGE E. BONIN ATTORNEY Feb, 24, 1970 G.E.'BONIN MECHANICAL LEVELI NG CHUCK 2 Shets-Sheet 2 Filed Nov. 16, 1966INVENTOR. GEORGE E. BONIN BY Y ATTORNEY United States Patent US. Cl.269-47 3 Claims ABSTRACT OF THE DISCLOSURE A leveling chuck forretaining Ware articles to be finished with substantial supporting areacontact by means of a plurality of upright support members each having aleveling arm pivotally connected thereto with flexibly mountedarea-contact support pads on each end of said leveling arms The recentneed for precision finishing ware articles, and particularly the bottomsurface of culinary ware with improved flatness tolerances, haspresented problems with regard to providing adequate means for suitablyretaining or holding the ware to be finished. Since precision flatnessis required to obtain optimum heat transfer between modern cookingsurfaces and bottom surfaces of culinary ware, it is necessary that theholding means not only initially level the uneven inside or backingsurface to its best average plane so as to facilitate the finishing ofthe outside surface to a predetermined thickness within acceptabletolerances, but also the holding means must adequately support thesurface to be finished so as to maintain it in a substantially levelplane and prevent flexing thereof, while compensating for irregularitieswhich may appear on the internal or backing surface In the past, avacuum chuck arrangement has been utilized in an endeavor to retain warearticles while the finishing operation is performed, by applying avacuum across the back of the surface to be finished. However it hasbeen found that the vacuum has a tendency to flex or to distort theunsupported surface being finished, with the result that when the vacuumis released, the finished surface distorts providing an unacceptableware article In addition ware articles have been potted with plaster,pitch, wax, etc, to a pitching block or holder in order to adequatelyretain them for precision finishing. However, the time and expenseinvolved in potting each ware article with its own individual pitchingblock does not lend itself to production line operations.

The present invention overcomes the problems heretofore encountered inchucking ware items for precision finishing, by providing a three-pointleveling support having a large dispersed surface contact area with theware, so as to avoid :point loading. Basically, my -improved chuckstructure includes a plurality of flexibly mounted support padspivotally connected to 3 upright members in such a manner so that theflexible pads firmly engage the inner or back side of a surface to befinished, while compensating for unevenness and irregularities in thesupported surface, and providing a substantially level and solidthree-point basic support therefore.

It thus has been an object of the present invention to provide animproved chuck structure for precision surface finishing, whichovercomes the problems heretofore encountered with previously knowndevices.

A further object of the invention has been to provide an improvedchucking device which firmly supports a ware article to be finishedwhile compensating for unevenness and irregularities in the supportedsurface.

Patented Feb. 24, 1970 ICE An additional object of the invention hasbeen to provide a tool for holding ware articles having an exteriorsurface to be finished wherein an uneven interior backup surface isleveled to its best average plane so as to facilitate the rapidfinishing of the outside surface to a predetermined thickness withindesired tolerances.

These and other objects of the invention will become more apparent tothose skilled in the art from the following specification andaccompanying drawings in which:

FIG. 1 is a top plan view of a novel chucking apparatus embodying myinvention.

FIG. 2 is a side elevational view of the apparatus shown in FIG. 1.

Referring now to the drawings, my improved chuck apparatus 10 is shownhaving a circular base member 11 provided with a pair of opposedclamping flange assemblies 12 for retaining a workpiece 13 having asupported inner surface 14 and an outer surface to be finished 15. Thebase 11 is provided with 3 arcuately equally-spaced upright supportmembers 16 which have a portion (not shown) extending downwardly intothe base. The support members 16 are each vertically adjustable by meansof a setscrew 17, which fixedly positions the portion extending Withinthe base 11.

Each upright support member 16 has a bifurcated upper end portion 18,pivotally retaining a leveling arm 29. A pivot pin 21 extends through araised boss portion 20 formed on leveling arm 19 so as to provide thearm with stability through a low center of gravity. A commerciallyavailable flexible stud type leveling support pad 22 is adjustablymounted adjacent each end of leveling arm 19. The leveling pad 22 ispreferably provided with a smooth-surfaced non-abrasive ware contactingmaterial, such as nylon ring portions 23. Each support pad 22 has adownwardly extending stem or shaft 24 flexibly connected thereto by aball and socket connection 24', which shaft is adjustably positionedwithin a vertical opening formed in arm 19, by means of a setscrew 25. Acollar 26 is adjustably positioned on each shaft 24 by means of asetscrew 27, to regulate the amount or degree of flexing permitted byits associated leveling support pad 22.

In addition, an adjustable wedge member 28 is slidably positioned underthe ends of each leveling arm 19, to limit the pivotal rocking movementof the arm. A tightening screw 29 fixedly positions each wedge member 28in a desired location, so as to limit the pivotal movement of levelingarm 19 about pivot pin 21. As shown in FIG. 1, an auxiliary vacuum chuck30, having a suction opening 31, may be provided centrally of the base11, although such a device is not necessary to obtain operable results.

A plurality of retaining guide pins 32, having nonabrasive spool-likeliners 33, may be positioned exteriorly of the workpiece 13 in order toguidably maintain the workpiece in position on the support pads. Asshown, when the workpiece is provided with a pair of flanges 13a, theguide pins 32 may be positioned on opposed flange portions 34 of theclamping flange assemblies 12.

The flange portion 34 of each clamping flange assembly 12 is providedwith a recessed portion 35 for pivotally receiving a bottom tongueportion 36 of a clamping device 37. The tongue 36 is pivotally retainedin place by a bolt pivot means 38. The clamping device 37 has an upperjaw 39 pivotally connected to the bottom tongue portion by pivotalconnecting means 40. An adjustable tightening screw 41 is provided toadjust the clamping pressure between upper jaw 39 and bottom tongueportion 36 of the clamping device 37. It has been found, however, thatthe clamping flange assemblies are not necessary to retain the workpiecein position upon the chuck apparatus when the apparatus is being rotatedabout its axial center, since the guide pins 32 suffice in maintainingthe positionment of the workpiece. However, should the chuck apparatusbe rotated eccentrically, the clamping flange assemblies provide addedassurance that the work article will be maintained in its properposition.

Since the bottom surface of the base member 11 is accurately machined toa desired flatness, the support pads of the chuck assembly are easilyadjusted and trued for positionment within a common plane by invertingthe chuck apparatus upon a flat level surface. A level may then beplaced upon the upwardly exposed bottom surface of the base 11, and theupright support members 16 appropriately adjusted by means of setscrews17. Fine adjustment of the support pads 22 can be accomplished bypositioning shafts or stems 24 by means of setscrews 25. Finally, thecollars 26 may be adjusted by means of setscrews 27 to provide theflexible leveling support pads 22 with a desired degree of flexibility.Also, slidable wedge blocks 28 may be fixedly positioned under levelingarms 19 so as to limit the pivoting action thereof about pivot pin 21.

In operation, a workpiece or ware article 13 is placed in an invertedposition upon the chuck apparatus 10. The inner surface 14 of theworkpiece, which may be uneven due to manufacturing tolerances, isfirmly supported by the flexible leveling pads 22 over a distributedsurface area. The pads 22, being flexibly mounted on shafts 24,compensate for irregularities in the inner surface, and through pivotalleveling arms 19 and upright support members 16, support pads 22 levelthe supported surface to its best average plane for facilitating thefinishing of outer surface 15. That is, upright support members 16 ineffect provide a three-point suspension, which of course providesstability, but by itself would induce point loading under compressivefinishing operations. However, leveling arms 19, provided with supportpads 22 at their opposite ends, alleviate the problem of point loading,and in effect provide a distributed surface area support, whileretaining the stability of a three-point suspension. Accordingly, withthe present invention it is possible to not only obtain improvedregistry and leveling stability, but also substantially uniform grindingpressure distribution thus facilitating both ease and precision inproviding a finished outer surface.

Although a now preferred embodiment of my invention has been set forthin great detail, it will be apparent to those skilled in the art thatvarious changes and modifications may be made thereto without departingfrom the spirit and scope thereof.

I claim:

1. Leveling chuck apparatus for retaining a ware article withsubstantial supporting area contact for precision finishing including abase member and a plurality of substantially equally spaced apartupright support members operatively mounted on said base member, whereinthe improvement comprises a leveling arm pivotally mounted on each saidupright support member, support pad means on end portions of each saidleveling arm including a leveling support pad for providing the warewith a substantially greater support area than that obtainable by saidend portions, means flexibly mounting said leveling support pad on eachsaid leveling arm to compensate for any unevenness in the supportedsurface and thereby provide substantial area contact with the ware, saidmeans for flexibly mounting said support pad means including avertically adjustable shaft for vertically adjusting said levelingsupport pad with respect to its associated leveling arm, means on saidshaft for limiting the degree of flexibility imparted by said pad,opposed clamping flange assemblies operatively connected to said basemember, and each of said flange assemblies being provided with aclamping device to securely clamp a workpiece in position on saidleveling chuck.

2. Apparatus for supplying area support contact to a ware article to befinished and retain such article in a level attitude for precisionfinishing which comprises, a base member, a plurality of arcuatelyspaced-apart adjustable support members mounted on said base member, aleveling arm pivotally mounted intermediate its ends on each saidsupport member, an adjustable shaft mounted on end portions of each saidleveling arm, a leveling support pad carried by each said adjustableshaft for .providing a substantial area contact with the ware article,each said leveling support pad being flexibly mounted on said shaft tocompensate for any local irregularity in the supporting surface andprovide area contact therewith, means for limiting the degree offlexibility of said leveling support pads, and means for limiting thepivotal movement of each said leveling arm.

3. Apparatus as defined in claim 2 wherein said means for limiting thedegree of flexibility of said leveling support pads includes collarmeans adjustably positioned on each said adjustable shaft intermediateits associated leveling arm and support pad, and said means for limitingthe pivotal movement of each said leveling arm comprises adjustablewedge means slidably mounted on said base member and engageable withsaid leveling arms to limit the pivotal movement thereof.

References Cited UNITED STATES PATENTS 1,933,639 11/1933 Schafer 269267X 2,379,244 6/ 1945 Miuton 269296 3,021,643 2/ 1962 Blanding.

ROBERT C. RIORDON, Primary Examiner L. GILDEN, Assistant Examiner US.Cl. X.R. 269296

